Exhaust bypass valves do not work in sport mode

[WROUPSTER]

Hello everyone,
I have a issue with the exhaust bypass valves on my 2009 Aston Martin DB9.
When I put fuse 22 in, the valves seem to work correctly (the noise is muffled between 1500 rpm and 4000 rpm) however when I press the Sport button, nothing happens and the noise remains muffled between this same range.
Obviously, when I remove fuse 22, the valves are open and the sound becomes louder.
Any ideas where the trouble might be coming from?
Many thanks for your help.

[Simpo Two]

Hi and welcome.

The Sport button doesn't open the valves, it's dependent on rpm. All Sport does is hold you in a lower gear for longer (and drops a cog even if trundling along straight and level).

[DB9S Paul]

As posted on Facebook, on the DB9 the Sport button has nothing to do with the exhaust, it's just more sporty map for the gearbox.

[WROUPSTER]

My bad, many thanks Paul.